Centralized traffic control system for railroads



Jan 26, 1937. R. M. PHINNEY 2,069,044

CENTRALIZED TRAFFIC CONTROL SYSTEM FOR RRILROADS Filed Aug. 7, 1930 2 Sheets-Sheet l w E a on no? 7IFNVENTOIE? BY ATTORNIEY R. M. PHINNEY jan. 26, 1937.

CENTRALIZED TRAFFIC CONTROL SYSTEM FOR RAILROADS Filed Aug. 7, 1950 2 Sheets-Sheet 2 Patented Jan. 26, 1937 more PATENT @EFIQE CENTRALIZED TRAFFIC CONTROL SYSTEM FOR RAILRGADS Application August 7, 1930, Serial No. 473,524

32 Claims.

This invention relates to systems for governing or regulating trafiic on railroads, and more particularly to a system of control for the callon indications of signals governing train movement over power-operated switches remotely controlled by a system of dispatching or centralized traiilc control.

The indications of signals, governing train movement over a track switch, are usually automatically controlled by track circuits, in accordance with the principles of block signaling, so that these signals may not clear, irrespective of the position of the switch or the manual control of the signals, if there is another train ahead. It is sometimes desirable, however, to permit a train to advance at low speed into a track section or block occupied by another train, and close up upon the train ahead; and this invention relates more particularly to the provi sion of adequate and safe means for permitting such a train movement.

Generally stated, in accordance with this invention, a low speed signal, sometimes termed a call-on signal, is given automatically, to permit a train movement over a switch even though the block ahead is occupied by another train, provided that such trains are travelling in the same direction. This low speed or callon signaling indication is given, as a result of special manipulation by the operator, dependent upon the d rection of train movement, and also upon the position and locked condition of the switch.

The various characteristic features, advantages, principles, and mode of operation of the invention are more conveniently considered after an explanation of the construction and operation of specific embodiments of the invention.

In the accompanying drawings, Fig. 1 illustrates in a diagrammatic and conventional manner one arrangement of relays and control circuits, embodying the invention; and Fig. 2 shows a modified form employing a different type of communication or supervisory control system.

Although the invention is applicable to various conditions, the particular embodiments illustrated show the invention applied to signals governing traffic over a single switch in a system of dispatching or centralized trafiic control; and it has been further assumed that this switch is at one end of a passing siding. This invention is not limited to any particular type of communication or supervisory control system by which the power operation of the track switch and the indications of signals are controlled from a distant control-ofiice, nor to any particular scheme of approach looking or block signaling; and to simplify the drawings and description, these means for accomplishing these various functions have not been shown at all, or are merely diagrammatically indicated.

Referring to the accompanying drawings, the switch SW is of the usual type and construction, and is operated by a suitable power-operated switch machine (not shown) under the control of a distant dispatcher or operator, in the manner shown and described, for example. in the application of S. N. Wight, Ser. No. 120,423, filed July 3, 1926. The full normal and reverse positions of the switch SW are repeated by suitable contacts. As illustarted, a threeposition polar relay WP, suitably controlled in accordance with the position and locked condition of the points of the switch SW (as indicated by the dotted line), is energized by one polarity of the current or the other, to shift its polar contacts 5 and 6 to a position correspond ing with the position of the switch points, these contacts 5 and 5 being in the open position when the switch points are in mid-stroke or unlocked.

The track adjacent the switch SW is provided with the usual detector track circuit having a track relay lT which is shown conventionally as a dotted line.

East-bound train movements (from left to right) over the switch SW are governed by signals l and IA, the signal i being the usual upper arm or high speed signal, and the signal IA the lower arm or low speed signal. nals may be of any suitable type, but are shown as color light signals. The signal I is capable of giving the usual three indications of green or proceed, yellow or caution, and red or stop, when the corresponding lamp designated G, Y, and R is lighted. The signal IA gives two indications. The signals 2 and 2A govern west-bound trafiic (from right to left) over the switch SW.

Associated with the signals l and lA are signal control relays IG and IAG, respectively, a home and distant or line relay 11-11), and a slow-releasing repeater line relay II-IDP. The line relay IHD is controlled by the track circuit AT, and other track circuits between the signal 2 and the signal (not shown) next in advance of the signal I,

and governing east-bound traffic in the same direction, all in accordance with the usual practice, and as shown and described in detail, for example, in the Wight application, Ser. No. 120,423, above mentioned. The repeater line re- These siglay IHDP is directly energized through the front contact 1 of the line relay IHD, so that whenever the line relay II-ID is energized, the relay IHDP is energized, and vice versa. The line relay II-ID is a neutral-polar relay which has the polarity of its energization determined by the indication of the signal next in advance in the usual way; and the signal lamps of the signal I are controlled by circuits (shown by dotted lines) which are governed by a polar contact 8 of the line relay IHD and front and back contacts 9 of the relay IG.

The control of the signals I and IA in accordance with this invention also involves the use of a directional stick relay ES, energized only by east-bound train movements, 2, stick relay AGS, and a relay or relays governed by the distant operator through the agency of a suitable communication or supervisory control system. In Fig.

1, this remotely controlled relay is illustrated as a neutral-polar relay Z, energized over a line wire II, extending to the distant dispatchers or control oifice CO, where its energization is determined by the position of a lever LV. When this lever LV is in the intermediate or center position shown, corresponding to the signals at stop, the relay Z is de-energized. When the lever LV is moved to one or the other of its extreme positions, corresponding to signals cleared either east or west, the relay Z is energized with current of one polarity or the other, and closes a neutral front contact i2, and shifts a polar contact I3 to a corresponding position. The movement of the polar contact I3 of the relay Z to the left or dotted line position corresponds to clearing the signals I or IA for an east-bound train movement over the switch SW. The relay Z-rnay also control the operation of the switch machine connected to the switch SW, as disclosed in the Wight application, Ser. No. 120,- 4.23, above mentioned; or the relay Z may be employed for the control of the signals only, with a separate relay governed over a separate line circuit acting to control the switch SW.

The principles and mode of operation of the system of this invention will best be demonstrated and made clear by an explanation of some typical train movements. The parts and circuits are shown in Fig. 1 in what may be termed the normal condition, the switch SW being in the normal po-- sition, the relays IHD and IHDP being energized, because no trains are present, and the signal control lever LV being on center and holding the signals IIA and also 2-2A, at stop.

Under these normal conditions, the relay AGS is energized by a pick-up circuit which may be traced from back contact I2 of relay Z, wires I4 and I5, relay AGS, wire I6, and front contact I! of track relay IT to This relay AGS is also energized by a stick circuit which may be traced from front contact I8 of relay AGS, wires I9 and I5, relay AGS, wire I6, front contact ll of track relay IT, to

Considering now one typical train movement, under which the low speed or call-on signal indication is given in accordance with this invention, assume that two east-bound trains on the main track are to make a meet with a west-bound train. The operator moves the lever LV to the position for an east-bound train movement, thereby energizing the relay Z with a polarity which shifts the polar armature I3 to' the left. Then, with the switch SW in the normal position, placed there by a suitable control (not shown) if not already in that position, an energizing circuit for the relay IG to clear the signal I is established and may be traced from front contact I2 of relay Z, wire 20, polar contact I3 of relay Z to the left, wires 22 and 23, front contact 24 of track relay IT, wire 25, contact 6 of relay WP in the normal position, wire 26, back contact 21 of relay IAG, wire 28, relay IG, wire 29, front contact 30 of relay IHDP, to This clears the signal I for the first east-bound train under consideration.

When this first east-bound train passes the signal I and drops the track relay IT to open its front contact 24, the relay IG is de-energized to cause the signal I to indicate stop. Also, the stick relay ES is picked up over a pick-up circuit which may be traced from wire 32, front con tact 33 of relay IHDP, wire 34, back contact 35 of track relay IT, wires 36 and 31, relay ES, to The entrance of the first east-bound train into the detector track circuit also de-energizes the stick relay AGS by opening its stick circuit at the front contact I! of the track relay IT.

When the east-bound train under consideration advances and drops the track relay 4T, the line relay IHD is de-energized, closing its back contact 38 to establish a stick circuit for the relay ES which. may be traced from back contact 38 of relay IHD, wires 39 and 40, front contact iI of relay ES, wires 42 and 31, relay ES, to The de-energization of the relay IHD also drops the relay I HDP, and the closing of its back contact 33 provides an additional stick circuit for the relay ES, including the back contact 33, wires 43 and 44 in multiple with the back contact 38 of the relay IHD.

The entrance of the first east-bound train in question into the detector track circuit is reported to the distant operator by the operation of the communication system in the usual way by means not shown, but shown and described in detail in the application of S. N. Wight, Ser. No. 120,423 above mentioned. The operator, being thus informed that the first east-bound train expected has arrived, and desiring to permit the second east-bound train to advance into the same block on the main track opposite the siding, as required in the example assumed, first puts his lever LV on center, de-energizing the relay Z.

As soon as the train in question has cleared the detector track circuit, the relay AGS is energized over the pick-up, circuit abovetraced. When the train clears the detector track circuit,

this fact being indicated in the control oflice by extinguishing the OS lamp, the operator may then move the lever LV back to the position to clear the east-bound signals, whereupon a circuit for energizing the relay IAG is established from through front contact I2 of relay Z, wire 20, polar contact I3 to the left, wire 22, front con tact 46 of relay ES (now energized), wire 41, contact of relay WP in the position corresponding to the switch normal, wire 48, front contact 49 of relay AGS (now re-energized), wire 50, relay IAG, to

This energization of the relay IAG clears the signal IA and gives a low speed or call-on indication for the second east-bound train under consideration, so that this train may advance beyond the signal IA and close up on the train ahead. After this second train has advanced and cleared the detector track circuit, the operator may reverse the switch SW and clear the signal 2A for the west-bound train making the meet in the example assumed.

When the relay IAG is energized, as just explained, to give a low speed or call-on indica tion, it breaks at its back contact 21 the energizing circuit for the relay IG, so that the signal I cannot clear even if the line relay IHD is energized. Also, the relay IAG closes at its front contact 5| a supplemental stick circuit for the relay ES, which may be traced from wires 32 and 52, front contact 5| of relay IAG, wires 53, M, and 40, front contact 4! of the relay ES, wires 42 and 31, relay ES, to Thus, even though the first east-bound train should, for any reason, advance beyond the next east-bound signal, permitting the relays IHD and IHDP to be energized, the stick relay ES is maintained energized, holding closed at its front contact 46 the control circuit for the relay IAG. This maintains the call-on indication; and since the relay IG is controlled through the back contact 21 of the relay IAG, the signal I cannot indicate caution or clear. This arrangement, which is optional and may be omitted if desired, prevents a change of signal and indications in the face of an approaching train, more particularly the flash of red or momentary stop indication at the signals I and IA, which might otherwise happen under the conditions explained, during the action of putting the signal IA to stop and clearing the signal I.

In the case of east-bound trains following one another on the main track, the operator leaves the signal control lever LV in the operated position for east-bound trafiic and the signal I may clear for a following train, as soon as a first train has advanced beyond the control limits for the line relay IHD. Even if the operator should put the signal control lever LV on center, picking up the relay A66 in so doing, the signal I rather than the low speed signal IA would be cleared, in case the operator should wait until the first train had advanced beyond the control limits for the signal I, before he moved his lever LV to the position for east-bound traffic, since the directional stick relay ES would then be de-energized, its stick circuits having been broken at the back contacts 33 and 38 of the relays IHD and II-IDP.

In case an east-bound train movement onto the siding is desired the signal IA may be cleared independently of the directional stick relay ES by energization of relay IAG over a circuit from front contact I2 of relay Z, wire 20, polar contact I3 to. the left, wires 22 and 54, contact 5 of relay WP in the position corresponding to the switch SW reversed, wire 48, front contact I19 of relay AGS, wire 50, relay IAG, to As this circuit includes front contact 49 of relay AGS, the detector track circuit must be unoccupied in order to clear the signal IA.

When the main track opposite the siding is occupied by a west-bound train, the signal I can not be cleared, because the line relay II-lD is deenergized by the presence of this train; and the signal IA cannot be cleared to give improper call-on indication with the switch in the normal position, since the directional stick relay ES has not been energized by the west-bound train in question. In other words, the signal IA can be cleared to give a low-speed or call-on indication, only for following train movements, because the directional stick relay ES must be energized to clear the signal IA with the switch in the normal position, and this can occur only when an east-bound train passes the signal I and IA.

It should, of course, be understood that when the low speed or lower arm signal IA is cleared, whether for a call-on indication, or for a train movement on to the siding, the operating rules require that the train accepting the signal indication shall proceed at low speed prepared to stop short of a train directly ahead.

If desired, the same scheme of providing a low speed or call-on indication may be used for the west-bound signals 2 and 2A.

From the foregoing it can be seen that, in accordance with this invention, no extra lever or control device is employed for giving the low speed or call-on indication. When the operator desires to set up for east-bound train movements over the switch SW in the normal position, he positions his lever LV accordingly and leaves it there. This allows the signal I to clear up for high speed moves in the usual way. If, however, the operator puts his signal lever LV on center, and then to the position for eastbound traiiic, while the first train is within the control limits of the signal I and the directional stick relay ES is picked up, then the relay AGS is picked up by such movement of the lever on center, and with the relay ES also energized, the relay IAG is energized to clear the low speed signal IA and give a call-on indication. Thus, while theoperator does not have a special lever or control device for the call-on indication, he is able to obtain this indication whenever desired by the special manipulation of his signal lever.

The relay AGS not only enables the operator to select between the upper arm or high speed signal I and the lower arm or low speed signal IA, according to the way in which the signal lever LV is manipulated while the switch SW is in a normal position, but also prevents re-energization of the relay I AG and clearing of the signal IA when an east bound train takes the siding in response to a clear signal and then passes beyond the detector track section. The siding is not ordinarily provided with track circuits, and a train taking the siding has control over the signal lA only while it is on the comparatively short detector track circuit; and unless the relay AGS were provided, the operator would have to be alert and should put his signal lever LV on center before the train taking the siding cleared this detector track circuit, in order to avoid energizing the relay IAG and clearing the signal IA when not desired by the operator. Such clearing of the signal IA might perhaps allow a closely following train to pass into the siding, contrary to the wishes of the operator, and is also disadvantageous, because the approach locking, such as shown and described in the Wight application, Ser. No. 120,423, above mentioned, would be-- come eifective upon clearing of the signal IA and might delay the operation of the switch SW for a following train that might be within the approach locking limits.

Fig. 2 shows a modified arrangement using a different type of communication system or supervisory control. In this modification, the communication system is assumed to be of the type shown and described, for example, in the prior application of N. D. Preston, et al., Ser. No. 455,304, filed May 24, 1930, which includes stepping or counting relays, such as a and b, in the control office and at the way station, which are operated sequentially one at a time in that order. The signal lever LV controls the energization of two relay SE and SW, which in turn control the energization of the relay PC on the successive steps. When the stepping relay a picks up on the first step, if the signal lever LV is in the righthand position, corresponding to signals clear eastbound, and the relay SE is energized, the relay F0 is energized on this first step. With the signal lever LV in the left-hand position, corresponding to the signals clear for west-bound traffic, and the relay SW is energized, the relay FC is de-energized on the first step (relay a picked up), and energized on the second step (relay I) picked up). On these two successive steps, in the simplified arrangement shown, these relays SGE and SGW at the station are operatively connected over a line circuit, as indicated by the dotted line 66,-to the contacts 6| of the relay FC, so that these relays SGE and SGW are energized on the corresponding step with current of one polarity or the other, depending on the condition of the relay F0 on that step. The relays SGE and SGW are of the biased two-position polar type, and shift their contact fingers 6265 to one position or the other, in accordance with the polarity of their energization; and these contacts are held in the position in which they are placed, until an impulse of the other polarity is received.

In a similar way, a two-position polar relay OSI, controlling the lighting of an OS lamp 66, is controlled on the first step, over an operative connection including a line circuit indicated by the dotted line 61, in accordance with the presence or absence of trains on the detector track circuit, which respectively cause the track relay IT to drop or pick up.

Assuming the operator wishes to give the callon indication, he positions the signal LV to the right which results in the energizing of the relay SGE at the field station with a polarity to shift its contact fingers 62 and 63 to the left or dotted line position. The relay SGW is energized with the opposite polarity to shift its contact fingers 64 and E55 to the right-hand position shown. Under these conditions, a wire 22*, corresponding to the wire 22 of Fig. 1, is energized from polar contact 64 of relay SGW to the right, wire 68, polar contact 62 of relay SGE to the left. This clears the signal I for east-bound traffic, in the same Way as above described.

When a first train has passed the cleared signal 5 putting it to stop and picking up the relay ES, as above described, and after the operator learns ofthe passage of this train by the lighting of the OS lamp 56, he puts the signal lever LV in the neutral position, whereupon the communication system operates to cause energization of the relays SG-E and SGW with a polarity to shift their contact fingers 62-55 to the righthand position. Under these conditions, the wire Id corresponding to the wire [4 of Fig. 1, is energized from contact 65 of relay SGW to the right, wire 69, contact 63 of relay SGE to the right. This energizes the relay AGS. When the signal lever LV is again returned to the righthand position to clear the signals for east-bound traffic, the signal IA is cleared to give the desired low speed or call-on indication for a second train in the same way as in the arrangement of Fig. 1, providing of course that the first train is still within the block causing relay IHD to be deenergized.

This modification of Fig. 2 makes provision so that the operator does not have to be careful in the manipulation of his signal lever, as he has to be in the arrangement of Fig. 1, in order to obtain the desired call-on indication. Referring to Fig. 1, it will be noted that the pick-up circuit for the relay AGS includes the front contacts I! of the detector track relay IT, so that this relay AGS cannot be energized until the train has cleared the detector track circuit. This means that, with such an arrangement of controlling circuits, the operator must wait until the train has cleared the detector track circuit before putting the signal lever on center. Also, with certain types of communication systems, where there may be a short delay in the transmission and reception of controls, the operator may fail to leave his signal lever on center long enough, after first putting it in that position, for thecommunication system to respond and cause energization of the relay AGS, with the result that the operator will not get the desired callon indication.

In the modification of Fig. 2, the operator may put the signal lever on center as soon as the train enters the detector circuit and the OS indication is received, and then at once restore it to the clear position, whereupon the desired callon indication will be given, without further manipulation on the part of the operator. This is accomplished by making the relay SE a stick relay controlled by the relay OSI;

If the operator places the signal lever LV to the right, when the detector track circuit is not occupied, and the contact 10 of the relay CS1 is at the right as shown, the relay SE is energized over a pick-up circuit from lever LV to the right, wire H, relay SE, wires 12 and 13,

contact 10 of relay OSI to the right, to The relay SE, once picked up, is stuck up by a. stick circuit from lever LV to right, wire 1|,relay SE, wire 12, front contact 14 of relay SE, to

When the OS indication is received of the arrival of the first train, the. operator may at once put the signal lever LV on center, and then'at once return it to the right-hand position to clear the signal IA later. When the signal LV is placed on center, the relay SE is de-energized and opens its stick circuit. When the operator returns the signal lever LV to the clear position, the contact 10 of the OS indication OSI being in the left-hand dotted line position due to the presence on the train of the detector track circuit, the relay SE cannot pick up again. When the relay SE is de-energized, the communication system acts to control the relays SGE and SGW to establish the pick-up circuit for the relay AGS; and as soon as the train leaves the detector track circuit, this relay AGS is picked up, and at about the same time the OS indication relay CS1 is restored to normal by the communication system, closing its contact 79 and permitting the relay SE to be again energized. The communication systemnow operates to shift the relay SGE to the clear position, giving the desired call-on indication.

The specific arrangement of relays and circuits shown and described, are merely specific and typical embodiments of the invention; and various modifications may be made in the specific arrangements, Without departing from the invention. Also, it should be understood that the devices and circuits of this invention are intended to be combined and used with other devices and circuits to constitute a complete system of traffic control.

What I claim is:-

1. In a trafiic controlling system for railroads, a high-speed signal and a low-speed signal governing trafiic in one direction over a track switch in one position, a remotely controlled device operable to hold said signals at stop or tend to cause one or the other to clear, track circuits for governing the high-speed signal, a stick relay energized by a train moving in the direction of trafiic governed by said signal, and a circuit for clearing the low-speed signal governed by said stick relay and said remotely controlled device.

2. In a traffic controlling system for railroads, a track switch at the end of a passing siding, a high-speed signal and a low-speed signal governing traffic over said switch toward said siding, means responsive to the presence of trains in a block in advance of said signal for governing the high-speed signal, a remotely controlled device operable to hold said signals at stop or tend to cause one or the other to clear, means governed by said remotely controlled device for clearing said high speed signal dependent upon the position of the switch and the presence of trains in said block, and means governed by said remotely controlled device for clearing said lowspeed signal if said switch is in the reverse position, or if said switch is in the normal position and said block is occupied by a train which entered it in the direction of trafiic governed by said signals.

3. In a trafiic controlling system for railroads, a track switch at the end of a passing siding, a low-speed signal governing traflic toward the siding; a directional relay energized by a train moving toward said siding and maintained energized while said train occupies a portion of track in advance of the signal, contacts opened and closed in accordance with the position of said switch, a remotely controlled device, and controlling circuits for said signal established by said remotely controlled device and governed by said contacts and said directional relay, whereby said signal may be cleared with the switch reversed independently of the presence of trains in advance of the signal, or may be cleared with the switch in the normal position and with a train travelling in the direction of traffic governed by the signal within said portion of track.

4. In a system of the type described, the combination with a power-operated track switch at the end of a passing siding, a high-speed and a low-speed signal governing traflic toward the siding, of a directional relay responsive to the direction of train movement, track circuits of a block in advance of said signal for governing the high-speed signal, and remotely controlled means for governing the low-speed signal in accordance with the position of the switch and the condition of said directional relay.

5. A system of the character described; a highspeed signal and a low-speed signal governing traffic over a switch; a track circuit of a block in advance of said signals for governing the highspeed signal; control means including a control lever for governing the indication of said, signals; and means responsive to the direction of train movement when it entered said block and the position of said lever, for clearing the low-speed signal.

6. In a traffic controlling system of the type described, a high-speed and a low-speed signal governing traffic in the same direction over a switch, a relay for controlling each signal, a directional stick relay responsive to the direction of train movement in said block, a stick circuit for said stick relay closed upon energization of the relay controlling the low-speed signal, and an energizing circuit for the relay controlling the high-speed signal including a back contact of the relay controlling the low-speed signal.

'7. In a trafilc controlling system for railroads, a high speed signal and a low speed signal for governing traffic in one direction over a block in advance of said signals, a remotely controlled device operable to hold said signals at stop or to allow one or the other of said signals to clear in accordance with traffic conditions in that block, means indicating trafiic conditions in that block including a stick relay having a pick-up circuit momentarily closed only by the passage of a train into the block in said one direction and having a stick circuit closed while such train is in that block, and means for clearing said low speed signal only when said stick relay is energized and said remotely controlled device is in a condition to allow such clearing.

8. In combination, a stretch of track, a high speed signal and a low speed signal governing traffic over-said stretch of track in one direction, means manually controllable for holding said high speed signal at stop or allowing said high speed signal to automatically clear in accordance with trafi'ic conditions in said stretch of track, means manually controllable and distinctively responsive to the direction of traflic movement through said stretch for holding said low speed signal at stop or causing said low speed signal to clear only when said high speed signal indicates stop due to trafiic movement through said stretch of track in said one direction.

9. In a trafiic controlling system of the type described, a high speed and low speed signal governing traific in the same direction through a block of railway track, a first relay for controlling said high speed signal, a second relay for controlling said low speed signal, a directional stick relay, a pick-up circuit for said stick relay closed only by the movement of a train through said block in said direction governed by said signals, a stick circuit for said directional stick relay closed when said second relay is energized, an energizing circuit for said first relay including a back contact of said second relay, an energizing circuit for said second relay including a front contact of said directional stick relay, and manually governable means for controlling said energizing circuits for said first and second relays.

10. In a trafiic controlling system of the type described, a high speed and low speed signal governing trafiic in the same direction through a block of railway track, a first relay for controlling said high speed signal, a, second relay for controlling said low speed signal, a directional stick relay, a pick-up circuit for said stick relay closed only by the movement of a train through said block in said direction governed by said signals, a stick circuit for said directional stick relay closed when said second relay is energized, an energizing circuit for said first relay including a back contact of said second relay, an energizing circuit for said second relay including a front contact of said directional stick relay, manually governable means for controlling said energizing circuits for said first and second relays, and other means requiring the opening of said energizing circuit for said first relay by said manually governable means upon a passage of a train before the energizing circuit for said second relay can be closed by said manually governable means for allowing the passage of a second train.

11. In a traffic controlling system for railroads, a signal governing trafiic over the track switch, a detector track section adjacent to said track switch and having a track relay, remotely controlled relay means for governing said signal, a signal control relay for controlling said signal, a stick relay having a pick-up circuit including a front contact of said track relay and a contact closed when said remotely controlled relay means lever. operable to clear or stop positions for governing said remotely controlled relay means, and means effective to restore said remotely controlled relay means to stop conditions by said control lever at any time and to clear conditions only when said detector track section is unoccupied.

12. In a trafiic controlling system for railroads, asignal governing tramc over a track switch, a control lever operable to proceed and stop positions, a detector track section associated with 'said track switch, relay meanslremotely controlled by said lever to proceedor stop conditions for causing said signal to give corresponding indications, means automatically operable for causing said signal to indicate stop upon the movement of a train over said detector track section said means holding said signal at stop until said relay means is restored to stop conditions and then returned to proceed conditions, and means allowing said control lever to position said relay means to stop conditions at any time and to position said relay means to proceed conditions only while said detector track section is unoccupied.

13. In a centralized traffic controlling system for railroads, a control ofiice, a field station, a

synchronous selector type communication system connecting said control ofiice and said field station, a track switch at said field station, a semi-' automatic stick signal for governing tramc over said track switch, relay means at said field station operable to proceed and stop conditions for governing said signal to corresponding proceed and stop indications, a control lever in the control ofiice operable to proceed or stop positions for transmitting corresponding proceed or stop controls to said relay means, and means permitting a stop control to be transmitted in accordance with said control lever at any time but permitting a proceed control to be transmitted in accordance with said lever only in the absence of a train on said track switch. 7

14. In a centralized traffic controlling system for railroads, a control office, a field station, a synchronous selector type communication system connecting said control oifice and said field station, a track switch at said field station, a detector track section associated with said track switch, a signal for governing traffic over said track switch, relay means at said field station operable to proceed and stop conditions for governing said signal to corresponding proceed and stop indications, a control lever in the control office operable to proceed or stop positions for transmitting corresponding proceed or stop controls to said relay means, and means permitting a. stop control to be transmitted in accordance with said control lever at any time but permitting a proceed control to be transmitted in accordance with said lever only when said detector track section is unoccupied,

15. In a centralized traffic control system for railroads, a control ofi'ice, a field station, a synchronous selector type communication system connecting said control office and said field station, a track'switch at said field station, a signal governing trafiic over said track switch, a detector track section associated with said track switch,

relay means operable to proceed stop conditions for causing said signal to give corresponding indi-' cations, means automatically operable at said detector track section said means holding said signal at stop until said relay means is operated to stop conditions andthenreturnedto proceed conditions,- acontrol lever in the control office operable to proceed and stop positions for transmitting correspo-ndi-ng; proceed or stop controls to saidrel aymeans at the field station, and means in the control office responsive to the occupied and unoccupied condition of said detector track section for permitting a stop control to be transmitted in accordance with said lever to said relay means at the field station at any time, but permitting a proceed control to be transmitted in accord-V ance with said-lever t'o-"said relay means at the field station only whefisai'd detector track section is unoccupied.

16. In a centralized trafiic' controlling system 7 for railroads, acontrol office, a field station,a synchronous selector type communication system connecting said control ofiice and said field statiorl,a jtracl: switch at said field station, a signal governing traffic over said track switch, a detector; track section associated with said track switch and having a track relay, remotely controlled relay means for governing said signal, a signal control relay for controlling said signal, a stick relay having a pick-up circuit including a front contact of said track relay anda contact closed when said remotely controlled relay means is governing said signal so as to cause it to indicate stop and having a stick circuit including its ovm front contact and said front contact of said track relay, an energizing circuit for said signal:

control relay including a front contact of said stick relay anda contact closed "when said'remotely controlled relay means is governing said signalso as t'o'allow it to indicate clear, a control lever in the control ofiice operable to proceed or stop positions for transmitting corresponding controls to said remotely controlled relay means at the field'station, means allowing said control l'everto transmit a stop control irrespective of the occupied condition of said detector track section, and means allowing said control lever to transmit proceed controls only when section 'is unoccupied.

l7. Ina trafiic controlling system for railroads, a section of railway track, a multiple aspect high speed signal and a multiple aspect low speed signal for governing t'rafiic in'one direction over said track section, each of said signals being capable of indicating'clear or stop, manually governable means for causing said high speed signal to indicate stop or proceed, means responsive to the presence of a train in said track section for causing said high speed signal to indicate stop irrespective of said manually governable means, and manually governable means distinctively responsive to the direction of traffic over said track section for causing said low speed signal to indinal for governing traffic in one direction over said track section, each of said signals being, capable of indicating clear or stop, manuallygovernable means for causing said high speed signal said detector track 1 to indicate stop or proceed, means responsive to the presence of a train in said track section for causing said high speed signal to indicate stop irrespective of said manually governable means, directional means for indicating the direction of travel of a train entering said track section, and manually governable means for causing said low speed signal to indicate clear when said track section is occupied by a train only when said directional means indicates that the said train entered said track section in the direction governed by said signal.

19. In a traffic controlling system for railroads; a section of railway track; a multiple aspect high speed signal and a multiple aspect low speed signal for governing traffic in one direction of said track section, each of said signals being capable of indicating clear or stop; manually operable means for causing said high speed signal to indicate stop or proceed, means responsive to the presence of a train in said track section for causing said high speed signal to indicate stop irrespective of said manually operable means; directional means for indicating the direction of travel of a train entering said track section; and means for causing said low speed signal to indicate clear after said high speed signal has been caused to indicate stop by said means responsive to train presence in said track section, said means being effective only if said manually operable means has been returned to such a condition as to cause said high speed signal to indicate stop, and then return to such a condition as to cause said high speed signal to indicate clear, and said means being efiective only if said directional means indicate that the train entered said track section in the direction governed by said signals.

20. In combination; a stretch of track, a high speed signal and a low speed signal for governing traflic over said stretch of track in one direction, each capable of indicating clear or stop; trafiic controlled means for automatically causing said high speed signal to indicate stop when said stretch is occupied; a manually operable lever having a clearing position and a stop position; means holding said high speed signal at stop when said lever is in its stop position, and

, allowing said high speed signal to indicate clear subject to said traffic controlled means when said lever is in its clearing position; means holding said low speed signal at stop when said lever is in its stop position, and causing said low speed signal to indicate clear only when said high speed signal indicates stop due to traffic conditions in said stretch of track when said lever has been put to its stop position and then to its clearing position subsequent to the automatic indicating of stop of said high speed signal.

21. In a traific controlling system for railroads, the combination with a low speed signal governing trafiic over a track switch, of a remotely controlled relay, a detector track circuit adjacent said track switch, a directional stick relay capable of being picked up in response to the movement of a train by said signal in a direction governed by said signal, another stick relay having its pick up and stick circuits controlled by said detector track circuit and having its pick up circuit also controlled by said remotely controlled relay, said another stick relay thereby being deenergized when a train occupies said detector track circuit, and means for controlling said signal to indicate clear only when said remotely controlled relay and said stick relays are picked up.

22. A signal control system comprising, a main signal governing traflic in a particular direction over a stretch of track, an auxiliary signal for giving a more restrictive indication than the indication of said main signal for train travel in the same direction over the same stretch, an auxiliary signal control relay for controlling said auxiliary signal, manually controlled means which maybe controlled to a proceed or to a stop position, and circuit means governed by said manually controlled means and traffic conditions in said stretch for energizing said auxiliary relay which circuit means may be rendered effective only if a train has entered said stretch in said particular direction and was still occupying the stretch while said manually controlled means still assumed a stop position.

23. A signal control system comprising, a main signal governing traffic in a particular direction over a stretch of track, an auxiliary signal for giving a more restrictive indication than given by said main signal for train travel in the same direction over the same stretch, an auxiliary signal control relay for controlling said auxiliary signal, manually controlled means which may be controlled to a proceed or to a stop position, and circuit means governed by said manually controlled means and traffic conditions in said stretch for energizing said auxiliary relay which circuit means may be rendered effective only if said manually controlled means is operated from the stop to the proceed position while a train which entered said stretch in said particular direction still occupies the same.

24. A signal control system comprising; a low speed signal for governing low speed train movements over a stretch of track in a particular direction; manually governable means which may assume a stop or a proceed position; a first stick relay having a pick-up circuit closed when a train is moving in a particular direction in said stretch, and having a stick circuit closed only until said train moves out of said stretch; a second stick relay having a pick-up circuit closed only when said manually governable means assumes the stop position, and having a stick circuit closed only if the first part of said stretch is unoccupied; and a second stick circuit for said first relay which may be closed only if said manually governable means assumes the proceed position while both of said stick relays are energized.

25. A signal control system comprising; a low speed signal for governing low speed train movements over a stretch of track in a particular direction; manually governable means which may assume a stop or a proceed position; a first stick relay having a pick-up circuit closed when a train is moving in a particular direction in said stretch, and having a stick circuit closed only until said train moves out of said stretch; a second stick relay having a pick-up circuit closed only when said manually governable means assumes the stop position, and having a stick circuit closed only if the first part of said stretch is unoccupied, a second stick circuit for said first relay which may be closed only if said manually governable means assumes the proceed position while both of said stick relays are energized; and a circuit for causing said signal to indicate proceed including in series front contacts of said two stick relays.

26. A signal control system comprising, a main signal and an auxiliary signal for governing railmerit of such train out of said stretch when said way traflic over a stretch of track in the same' direction, manually controllable means which if in one position tends to cause both of said signals to indicate proceed and if in another position holds both of said signals at stop, means in said stretch responsive to the presence of a train in said stretch for holding said main signal at stop, and means responsive to the movement of a train through said stretch in said direction only for permitting said auxiliary signal to indicate proceed.

27. A signal control system comprising, a main signal and an auxiliary signal for governing railway trafiic over a stretch of track in the same direction, manually controllable means which if in one position tends to cause both of said signals to indicate proceed and if in another position holds both of said signals at stop, means in said stretch responsive to the presence of a train in said stretch for holding said main signal at stop,

means responsive to the movement of a train through said stretch in said direction only for permitting said auxiliary signal to indicate proceed, and means for maintaining said auxiliary signal at proceed in spite of movement of such train out of said stretch.

28. A signal control system comprising, a main signal and an auxiliary signal for governing railway traiiic over a stretch of track in the "same direction, manually controllable means which if in one position tends to cause both of saidsignals to indicate proceed and in another position holds both of said signals at stop, means in said stretch responsive to the presence of a train in said stretch for holding said main signal at stop,

means responsive to the movement of a train through said stretch in said direction only for permitting said auxiliary signal to indicate proceed, and means for preventing clearing of said main signal upon movement of such train out of said stretch when said auxiliarysignal indie to proceed. g 1 29. A signal control system comprising, a main signal and an auxiliary signal for governing rail Way trafiic over a stretch of track in the same direction, manually controllable means which if in one position tends to cause both of said signals to indicate proceed and if in another posi tion holds both of said signals at stop, means in said stretchresponsive to the presence ofa train in said stretch for holding said main signal at stop, means responsive to the movement of a train through said stretch in said direction only for permitting said auxiliary signal to indicate proceed, means for maintaining said auxiliary signal at proceed in spite of movement of such train out of said stretch, and means for preventing clearing of said main signal upon moveauxiliary signal indicates proceed.

' ing said main signal at stop, means responsive to the movement of a train through said stretch in 7 said direction only for permitting said'aux'iliary signal to indicate proceed, means for maintaining said auxiliary signal atproceed in spite of movement of suchtrain out of said stretch, means for.

preventing clearing of said main signal upon movement of such train out of said stretch when said auxiliary signal indicates proceed, and means responsive to the movement of a second train through said stretch for causing said auxiliary signal to indicate stop. r

31, A signal control system comprising, a main 7 signal and an auxiliary signal for governing railway trafiic over a stretch of track in the same direction, manually controllable means which if in one position tends to causelboth of said signals to indicate proceed and if in another position holds both of said signals at stop, means in said stretch responsive to the presence of a train in said stretch for holding said main signal at stop, means responsiveto momentary movement of said manually controllable means to said another position for allowing said auxiliary signal to indicate proceed when a first train is in said stretch, and means for maintaining said auxiliary signal at proceed independently of movement of such train out of said stretch. i r

32. A signal control system comprising, a main signal and an auxiliary signal for governing railway trafiic over a stretch of track inthe same direction, manually controllable means which if in one position tends tocause both of said signals to indicate proceed and if in another 'po'si tion holds'both of said signals at stop, means in said stretch responsive to thepresence of a train in said stretch for holding said main signal at stop, means responsive to momentary'movement of said manually controllable means to said another position for allowing said auxiliary signal to indicate proceed when a first train is in said stretch, means for maintaining said auxiliary signal at proceed independently of movement of such train out of said stretch, and means responsive to the movement of a second train through said stretch for causing said auxiliary signal to indicate stop. 7

ROBERT M. PHINNEY. 

